Its sign or badge was also agreed upon, namely, a red cross on a white ground, which was to be worn on the arm by all persons acting with or in the service of the committees enrolled under the convention. The treaty provides for the neutrality of all sanitary supplies, ambulances, surgeons, nurses, attendants, and sick or wounded men, and their safe conduct when they bear the sign of the organization, viz: the Red Cross. Although the convention which originated the organization was necessarily international, the relief societies themselves are entirely national and independent; each one governing itself and making its own laws, according to the genius of its nationality and needs. It was necessary for recognition and safety, and for carrying out the general provisions of the treaty, that a uniform badge should be agreed upon. The Red Cross was chosen out of compliment to the Swiss republic, where the first convention was held, and in which the central committee has its headquarters. The Swiss colors being a white cross on a red ground, the badge chosen was these colors reversed. There are no "members of the Red Cross," but only members of societies whose _sign_ it is. There is no "_Order of the Red Cross_." The relief societies use, each according to its convenience, whatever methods seem best suited to prepare in times of peace for the necessities of sanitary service in times of war. They gather and store gifts of money and supplies; arrange hospitals, ambulances, methods of transportation of wounded men, bureaus of information, correspondence, etc. All that the most ingenious philanthropy could devise and execute has been attempted in this direction. In the Franco-Prussian war this was abundantly tested. That Prussia acknowledged its beneficence is proven by the fact that the emperor affixed the Red Cross to the Iron Cross of Merit. The number of governments adhering to the treaty was shortly after increased to twenty-two and at the present date there are forty-two. The German-Austria war of 1866, though not fully developing the advantages of this international law, was yet the means of discovering its imperfections. Consequently, in 1867 the relief societies of Paris considered it necessary that the treaty should be revised, modified and completed. Requests were issued for modification. The International Committee transmitted them to the various governments, and in 1868 a second diplomatic conference was convened at Geneva at which were voted additional articles, improving the treaty by completing its design and extending its beneficial action to maritime warfare.